Question

The energy stored in a magnetic field is given by ____________ where L=self-inductance and Rl=reluctance.

(a) 1/2 Li^2

(b) 1/2 (mmf*Rl)^2

(c) 1/2∅Rl

(d) 1/2 φ^2i

This question was addressed to me at a job interview.

Asked question is from Singly Excited Magnetic Systems in portion Magnetic Circuits of Electrical Machines

Answer 1

Right option is (a) 1/2 Li^2

The explanation is: We know that Wfld=1/2 φi and L=φ/i, thus Wfld=1/2 Li^2.